Wall-supported skimmer for swimming pools and the like

ABSTRACT

The housing of a skimmer for mounting on the sidewall of a swimming pool has a flow passage thereinto and a discharge flow outlet therefrom. A float member rises and falls with the water level and provides a conduit into the lower portion of the housing so that matter may be skimmed from near the surface and carried into the housing. A passageway bypassing the float member may be controlled to adjust the rate of waterflow therethrough, and appropriate means for supporting the skimmer on the pool sidewall is provided.

United States Patent [72] Inventors Joseph Diemond Simsbury; Melvin Y. Gershman, West Hartford; Fred A. Ravreby, Framingham, all of Mass. [21] Appl. No. 33,213 [22] Filed Apr. 30, 1970 [4S] Patented Nov. 2, 1971 [73] Assignee Coleco Industries, Inc.

Hartford, Conn. Continuation-impart of application Ser. No. 797,396, Feb. 7, 1969, now Patent No. 3,508,661. The portion of the term of the patent subsequent to Apr. 28, 1987, has been disclaimed.

[54] WALLSUPPORTED SKIMMER FOR SWIMMING POOLS AND THE LIKE 10 Claims, 7 Drawing Figs.

[52] U.S. CI i.

[51] Int. Cl E04h 3/20 [50] Field of Search 210/169 [56] References Cited UNITED STATES PATENTS 3,186,550 6/1965 Beduhn 210/169 3,508,661 4/1970 Diemond et a1. 210/169 Primary ExaminerReuben Friedman Assistant Examiner-T. A. Granger Attorney-Peter L. Costas ABSTRACT: The housing of a skimmer for mounting on the sidewall ofa swimming pool has a flow passage thereinto and a discharge flow outlet therefrom. A float member rises and falls with the water level and provides a conduit into the lower portion of the housing so that matter may be skimmed from near the surface and carried into the housing. A passageway bypassing the float member may be controlled to adjust the rate of waterflow therethrough, and appropriate means for supporting the skimmer on the pool sidewall is provided.

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WALL-SUPPORTED SKIMMER FOR SWIMMING POOLS AND THE LIKE CROSS REFERENCE TO RELATED APPLICATION The present application is a continuationin-part of applicants copending U.S. application Ser, No. 797,396, filed Feb. 7, 1969, now patent number 3,508,661 and entitled SKIMMER FOR SWIMMING POOLS AND THE LIKE.

BACKGROUND OF THE INVENTION It is customary to provide gutters or overflow devices on larger swimming pools to remove the surface portion of the water which contains scrum. This also removes floating debris such as leaves, lint, hair and the like to maintain the cleanliness of the pool. Generally, this overflow or skimmed surface portion is circulated through a screen or strainer and then through a filter of sand or other suitable filter media before being reintroduced to the pool.

With above-ground swimming pools particularly, and with some below-ground pools, skimming devices including a housing into which the water flows are frequently employed at only one point about the sidewall. Some form of a weir or float that is responsive to water level in the housing is relied upon to control waterflow into the interior of the housing and thereafter through the discharge passage therefrom. In addition, it is customary to provide vacuum cleaner attachments which are used to remove debris below and on top of the sur-.

face of the water, and the water drawn off by this attachment is generally screened filtered and returned to the pool.

Since the volume of water flowing from the surface into the overflow device of surface skimmer will vary with the level and turbulence of the water, it is customary to provide a selectedvolume of waterflow through the filter from a point below the surface to avoid injury to the pump and to maintain optimum filtering action. Accordingly, the weir or float element in the skimmer must control skimmer flow in cooperation with flow through the submerged passage.

Many devices of the skimmer type have been proposed and marketed. Some of these employ pivotable weirs and others floating plates, floating curtains and telescoping intakes. Some permit the vacuum cleaner to be plugged into the discharge flow passage of the skimmer housing to the filter, and others provide a below-surface bypass. However, such devices generally require disassembly of parts to vary the bypass flow or to permit insertion of the vacuum cleaner hose thereinto.

The previously mentioned copending application discloses a relatively simple, self-contained skimmer that provides facile means for control of water flow therethrough, and to which a vacuum cleaner hose may be readily connected for operation in a desireable manner. Although the novel devices disclosed therein are highly effective in operation, there has remained a need for skimmers of equivalent performance at lower cost and for mounting readily upon the sidewall of the pool without an aperture therein.

Accordingly, it is an object of the present invention to provide a novel, self-contained skimmer for hanging upon the sidewall of swimming pools and the like, which enables facile, close control of the water skimmed from the surface during use as well as of the volume of water withdrawn from below the surface ofthe pool.

It is also an object of the invention to provide a novel skimmer that utilizes a unique throttle plate assembly for control of the flow of water therethrough.

Another object is to provide such a skimmer which enables facile connection of a vacuum hose thereinto from the inside of the swimming pool, whereby vacuum of the pump may be concentrated on the liquid passing through the hose.

Still another object is to provide a skimmer that employs a minimum number of parts, wherein the housing may be of unitary construction and adapted for support upon a swimming pool sidewall to reside substantially entirely therewithin.

A further object is to provide such a skimmer which may be readily and economically fabricated from a synthetic plastic material, and which is relatively simple to adjust and maintain and may be readily disassembled for cleaning and repair.

SUMMARY OF THE INVENTION It has now been foundthat the foregoing and related objects can be readily attained in a surface skimmer comprising a housing having a sidewall with at least one opening therein providing a flow passage thereinto, and also having a flow outlet therefrombelow the one opening; and adjacent the lower end ofthe housing for discharge of liquid therefrom. A float assembly is provided in the housing and includes a float member adapted to 'rise and fall substantially vertically with changes in the level of water in the housing. The float assembly also has a base member secured in the housing below the flow passage therein, and a vertically extensible sleeve extending between the base member and the float member. The

base and float members have apertures therein about which the sleeve extends to provide a flow conduit from the upper surface of the float member, through the sleeve, and into the lower portion of the housing for discharge of liquid through the flow outlet. At least one of the housing and the base plate of the float assembly has a control flow passage therein for passage of liquid into the interior of the housing below the base plate to bypass the flow conduit through the sleeve. Control means is,present in at least one of the float member aperture and the control flow passage for varying the flow of liquid from the tank therethrough and into the housing and the flowQ outlet thereof; the control means provides adjustability of flow rates through a multiplicity thereof. The housing has means for supporting it on the sidewall of a tank to suspend it entirely inwardly thereof.

In preferred embodiments of the invention the float member of the skimmer includes buoyant means providing enhanced buoyancy thereto. It may also have an upstanding wall about the flow aperture therein providing a channel opening at the one opening in the housing sidewall for receiving liquid passing therethrough. Most desirably the skimmer includes a strainer member removably mounted in the housing above the discharge flow outlet and it may also include means releasably engaging the float assembly in the housing, so that it is removable therefrom to permit access to the strainer for the removal thereof.

In additional preferred embodiments, the control flow, passage is provided in the housing, and the control flow passage and said one opening are provided by a single aperture in the housing sidewall. The base member of the float assembly extends across the single aperture to define the control flow passage below it and the one openingthereabove. In such a skimmer it is particularly preferred that the control means comprise a throttle plate assembly positioned over the lower portion of the housing sidewall aperture, and having at least one control flow opening therethrough and a movable member mounted thereon for progressively closing the control flow opening to provide a multiplicity of flow rates therethrough.Preferably, the throttle plate assembly has a plurality of suchcontrol flow openings and an opening therein is adapted to receive the end of a vacuum cleaner hose fitting. Most desirably, the throttle plate assembly comprises an elongated backing plate having a solid portion adjacent one end and the control flow openings adjacent the opposite end thereof. The movable member is provided by a throttle plate that is mounted against one surface of the backing plate to slide from a position of registry with the solid portion to a position overlying, and thereby closing, the control flow openings. In this manner, the throttle plate and the solid portion may cooperate to completely block the flow of liquid through the control flow passage in which the throttle plate assembly is mounted.

Certain objects of the invention can be obtained in a surface skimmer for mounting on the sidewall of a liquid-containing tank andcomprising a housing having a sidewall with at least one opening therein providing a flow passage thereinto, said housing also having a flow outlet therefrom below the one opening and adjacent the lower end thereof for discharge of liquid; a float assembly in the housing includes a float member adapted to rise and fall with the level of water therein, and to control the flow of water into the lower portion of the housing and through the flow outlet. The housing has a control flow passage in the sidewall thereof below the float assembly for passage of liquid into the interior of the housing, by passing the float member. A throttle plate assembly is provided in the control flow opening for varying the effective size thereof and thereby the flow of liquid from the tank therethrough, the throttle plate assembly providing adjustability of flow rate through a multiplicity thereof. In this embodiment, the assembly comprises an elongated backing plate having a solid portion adjacent one end and at least one control opening adjacent the opposite end thereof. A throttle plate that is dimensioned and configured to block the control flow opening in the backing plate when in registry therewith is provided in the assembly, which additionally has means mounting the throttle plate against one surface of the backing plate for progressive sliding movement thereof. The throttle plate may thereby be moved from a position of general registry with the solid portion to a position of registry over the control flow opening in the backing plate, and in the latter position the throttle plate cooperates with the solid portion to block the flow of liquid through the throttle plate assembly. The skimmer also includes support means on the housing for mounting on the sidewall of a tank, and when the backing plate has a plurality of flow openings therein, as is preferred, most desirably one of those openings is adapted to receive the end of a vacuum cleaner hose fitting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a surface skimmer embodying the present invention in condition for vacuuming, and with the mounting bracket thereof fragmentarily illustrated;

FIG. 2 is a front elevational view, in partial section, of the skimmer of FIG. 1 as supported upon a swimming pool with the supporting wall section shown in phantom line and with the float plug removed;

FIG. 3 is a plan view thereof with the float plug removed;

FIG. 4 is a sectional view thereof along the line 4-4 of FIG. 3 showing in phantom line the pool wall and in dotted line the water level in the pool;

FIG. 5 is an exploded fragmentary perspective view of the throttle plate assembly utilized in the skimmer;

FIG. 6 is a fragmentary sectional view along the line 6-6 of FIG .2; and

FIG. 7 is an exploded side elevational view of the float assembly and strainer basket, with portions of the float in section and with the float member illustrated in phantom line in its extended position.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Turning now in detail to the appended drawings, therein illustrated is a surface skimmer embodying the present invention suspended inwardly of a swimming pool from the upper rail 10 of the sidewall thereof. The skimmer comprises an integrally formed housing, generally designated by the numeral 12, having a sidewall portion generally designated by the numeral l4 and a receptacle base portion that is generally designated by the numeral 16. The sidewall portion 14, which is generally C-shaped in horizontal cross section and thereby defines a frontal passageway 18 into the housing 12, has a top section 19 and a bottom section 20 of reduced width and depth connected thereto by side web portions 70 and the rear shoulder portion 30. The sidewall of the base portion 16 tapers downwardly to a relatively small bottom wall 22 with a circular aperture 24 therein. A cylindrical boss 26 depends from the bottom wall 22 about the aperture 24 and provides a fitting frictionally engaged with a discharge hose 28 (shown in FIG. 1).

As is best seen in FIG. 2, the narrow shoulder 30 at the rear of the housing 12 is slotted to allow passage therethrough of one end of the hanger strap 32, the lower end thereof having been flattened or otherwise distorted to prevent it from passing upwardly entirely through the slot. The upper end of the strap 32 is provided with a pair of holes 34, through which pass screws 36 for engagement in two of the multiplicity of threaded holes 38 formed in the vertical leg 39 of the L- shaped hanger bracket, generally designated 40. The lower screw 36 causes the ends of the strap 32 and the bracket 40 to securely grip the upper edge of the sidewall portion 14; the upper screw 36 passes through a spacer washer 42, and provides added security for supporting the housing 12. The horizontal leg 44 of the bracket 40 overlies the top rail 10 and is provided with a hole 46, through which passes a screw 48 securing the entire assembly on the rail 10 to prevent inadvertent or unauthorized removal thereof. It will be apparent that the hanger employed may take any of various forms, depending upon the level of permanency and security desired, and that the distance that the housing 12 hangs below the rail 10 may readily be altered by engaging the screws 36 in different ones of the threaded holes 38.

As is best seen in FIG. 5, the throttle plate assembly, generally designated by the numeral 50, is constructed of a rear rectangular plate 52 having a circular openings 54 adjacent one end, a rectangular flow opening 56 next to the circular opening 54, and a solid portion 58 at the other end constituting at least about half the length of the plate 52. A rectangular door or throttle plate 60 is positioned against the rear plate 52, and has a small finger grip tab 62 to facilitate its movement across the rear plate 52. A frame member 64 having an inner peripheral shoulder 66 is thereafter secured against the rear plate 52 with the throttle plate 52 slidably seated in the channel formed between the shoulder 66 and the adjacent portions of the rear plate 52. An outer shoulder 68 is provided about the side and bottom elements of the frame member 64, so that the entire assembly 50 may be seated in the bottom of the frontal passageway 18 of the sidewall portion 14 in the manner illustrated in FIG. 6. Thus, the edge ele-' ments defining that portion of the passageway 18 are engaged in the groove that is cooperatively formed by the outer shoulder 68 of the frame member 64 and the adjacent portions of the rear plate 52. The throttle plate assembly may be permanently fixed in this position if so desired.

The frame member 64 is about equal in height to the bottom section 20 of the sidewall portion 14. Therefore, its upper surface lies in a common, substantially horizontal plane with the rear shoulder 30 and the webs 70 at the sides of the housing 12 so that the upper surfaces thereof provide underlying peripheral support for the base plate 72 of a float assembly. A small, generally conical boss 76 having a short upstanding post 78 is provided at the top of the front face of the frame member 64, and a small locking tab 80 is pivotally secured on the post by a locknut 82. The tab 80 is shown in FIG. 1 positioned over the base plate 72, and the base plate 72 is cooperatively configured to seat within the housing 12, whereby the float assembly is securely held against the underlying support elements provided therein and previously described. Pivoting the tab 80 to the position shown in phantom line permits removal of the float assembly from the housing 12, such as for cleaning, repair, etc.

The base plate 72 has a centrally located circular aperture 84 with a circumferential collar 86 extending upwardly therefrom. One end of an expansible accordian-type tubular sleeve 88 of wire-reinforced plastic material is frictionally enproviding the hypotenuse of the shoulder elements 96 taper outwardly towards the front of the float member 74, and define, in cooperation with the bottom wall 94 and the inside walls 100 thereof, a flow-directing channel for diverting liquid flow toward the aperture 92 therein. The shoulder elements 96 are filled with a relatively low-density synthetic resin foam 102 to enhance the buoyancy of the float member 74.

Below the base plate 72 of the float assembly and within the well 112 that isde'fined in the receptacle base portion 16, is seated an open-weave-type strainer basket 110. The basket 110 has an outwardly extending flange 114 about its upper periphery which rests upon the corresponding surfaces of the well 112, thereby maintaining spacing between the sides and bottom of the basket 110 and the well 112 to ensure adequate flow of liquid therebetween. As is best seen in H6. 6, a cylindrical vacuum hose fitting 116 is frictionally engaged in the circular aperture 54 formed in the rear plate 52 of the throttle assembly 50. The fitting 116 has a circumferential flange 118 spaced from the inner end thereof to prevent the fitting 116 from passing entirely through the aperture 54 and into the space within the housing 12 below the base plate 72. The skimmer is completed by the provision of a cover 104 for the aperture 92 formed in the bottom wall 94 of the float member 74. The cover 104 has a depending annulus 106 on which it is frictionally engageable within the aperture 92, and it has a small finger grip 108 projecting from its upper surface to facilitate removal.

Turning now in detail to the operation of the illustrated embodiment, the throttle plate 60 will normally be in position so that at least one of the openings 54, 56 in the rear plate 52 of the throttle assembly 50 is partially open so as to permit passage of a selected volume of water therethrough. This amount or volume of water is adjusted by sliding the throttle plate 60 by means of the tab 62 thereon across the openings -54, 56 until the sight glass of the pump (not shown) is free frombubbles, or the sound of the pump indicates a desired flow of water therethrough. Depending upon the size of the pool and the size of the pump, this may entail complete closure of the rectangular opening 56 and partial closure of the circular opening 54, for which purpose the hose fitting 116 may be entirely removed to permit the plate 60 to slide behind the opening 54. Alternatively, the rectangular opening may be partially opened and the circular opening fully opened by sliding the plate further to the right, and if desired the hose fitting 116 may be left in the aperture 54 and closed by means of an appropriate cap (not shown) thereover.

Under normal operating conditions, water is flowing from the pool through the one or both of the throttle openings 54, 56 and into the body of the housing 12 from which it is discharged through the cylindrical portion 26 after it passes through the strainer basket 110, which serves to remove any readily screenable debris. This water is conducted by the hose 28 to the pump and filter (not shown) and is then returned therefrom to the pool through another hose (not shown) and back into the body of the pool through a fitting (not shown) in the sidewall. The float member 74 will normally tend to float with the upper surface thereof about one-quarter to'l inch below the surface of the water (as suggested in FIG. 4) so that a surface portion containing any scum or debris will tend to flow into the channel thereof defined by the walls 94, 100. The water entering into the channel of the float member 72 will rapidly flow through the apertures 92, 84 and thence through the strainer basket 110 and cylindrical portion 26 into the hose 28 for transport to the filter (not shown).

When it is desired to use the vacuum cleaner to remove such debris as may have accumulated below the surface of the water, the hose fitting 116 may be inserted readily into the circular opening 54 of the throttle plate assembly 50. The throttle plate 60 is slid toward or into the closed position shown in FIG. 1 and the cover 104 is engaged over the aperture 92 in the float member 74, sothat the suction of the pump (not shown) is essentially directed through the hose fitting 116.

Periodically the basket 110 must be removed to dispose of the debris which has collected therein, this operation is extremely simple, and evidences one of the advantages of the illustrated structure. Thus, as has been previously described, the locking tab is simply pivoted to the alternate position shown in phantom line in FlG. 1. This disengages the base plate 72 and permits it to be lifted from the supporting surfaces provided by the elements 30, 50 and 70, so that the float assembly can be removed in its entirety from the housing 12 through the opening at the top of the sidewall, 14. At this time the basket is fully exposed and may readily be removed for cleaning; the procedure indicated is reversed for reassembly.

Another advantage of the invention is the simplicity of installation that the skimmers having a unified or integral housing afford. As has been described, a suitable bracket may be fixed on the housing and employ a single screw for engagement in the top rail of a swimming pool sidewall, to mount the skimmer thereon. Even more conveniently, a hook-shaped bracket may be used to merely hang the skimmer over the wall of the pool, albeit with less security against inadvertent or unauthorized removal. Certain of the devices disclosed are suited for installation in an aperture through the wall of the pool, and this type of mounting is fully described in the copending application, hereinbefore referred to.

Thus, the skimmer assembly of the present invention is ideal from installation, adjustment and maintenance standpoints. The float assembly and strainer basket may be readily removed, and the volume of water flowing past the float. assembly into the discharge passage of the housing or bypassing the float assembly may be varied in a very convenient manner. The preferred structure has a throttle plate assembly in the housing for most facile adjustment; however, the throttle aperture may be in the baseplate of the flloat assembly or in the float member. Desirably, the aperture in the float member may have a throttle or control means thereon to control the depth of skimming as wellas to adjust the-volume of flow into the housing.

The ability to plug the vacuum cleaner hose into the throttle plate assembly is extremely beneficial, and the entire volume of waterflow passes through the strainer bracket. Although other types of devices for near surface skimming may be em- .ployed, the'preferred structures use an extensible float assembly of the type described.

The several parts of the skimmer are preferably fabricated from synthetic -plastic material such as polyethylene, polypropylene, ABS (graft copolymers of styrene/acrylonitrile on butadiene or other rubbers) or like materials having good impact resistance and low-temperature properties, so as to provide long life and relative freedom. from corrosion or attack from the chemicals usually dissolved in the pool water. Although thermoforming and compression molding may be used where the configuration of the several components permits, injection molding of synthetic plastic material has proven particularly advantageous. The housing may be readily and inexpensively thermoformed in a single operation to provide a one-piece, integral member; and the throttle plate assembly is readily fabricated from threesimple and inexpensive parts.

Thus, it can be seen from the foregoing detailed description and the illustrated embodiment that the present invention provides a novel, ,selfcontained skimmer for the sidewall of swimming pools and the like, which enables facile, close con trol of the water skimmed from the surface as well as of the volume of water withdrawn from below the surface the pool. The skimmer may utilize a unique throttle plate assembly for control of the flow of water therethrough, and it enables facile connection of a vacuum hose thereinto from the inside of the swimming pool, whereby vacuum of the: pump may be concentrated on the liquid passing through the hose. A minimum number of parts may be employed in the skimmer, and the housing may. be of unitary construction and adapted for support upon a swimming pool sidewall to reside substantially entirely therewithin. The skimmer may be readily and economically fabricated from a synthetic plastic material, and it may be relatively simple to adjust and maintain, and readily disassembled for cleaning and repair.

Having thus described the invention, we claim:

1. In a surface skimmer supportable on the sidewall of a liquid-containing tank and adapted for disposition substantially entirely inwardly thereof, the combination comprising:

a. a unitary housing having a sidewall with at least one large opening in its front face providing a flow passage thereinto, said housing also having a flow outlet therefrom below said one opening and adjacent the lower end thereof for discharge of liquid;

b. a slide plate assembly mounted on said housing in the lower portion of said large opening and extending thereacross to provide a closure for said lower portion of said opening;

C. a float assembly in said housing including a float member adapted to rise and fall substantially vertically with changes in the level of water in said housing, a base member secured in said housing with its front portion supported on said plate assembly and a vertically extensible sleeve extending between said base member and said float member, said base member extending transversely of the internal cavity defined by said sidewall of said housing to provide a transverse flow barrier therein, said float and base members having apertures therein about which said sleeve extends to provide a flow conduit from the upper surface of said float member, through said sleeve, and into the lower portion of said housing for discharge of liquid through said flow outlet; said throttle plate assembly providing adjustability of flow rate through a multiplicity of flow rates and comprising an elongated backing plate having a solid portion adjacent one end and at least one control flow opening adjacent the opposite end thereof, a throttle plate dimensioned and configured to block said control flow opening when in registry therewith, and means mounting said throttle plate against one surface of said backing plate for progressive sliding movement thereof from a position of registry over said control opening wherein said throttle plate cooperates with said solid portion to block the flow of liquid through said throttle plate assembly; and

d. support means on said housing for mounting on the sidewall ofa tank.

2. The skimmer of claim 1 wherein said float member includes buoyant means providing enhanced buoyancy thereto.

3. The skimmer of claim 2 wherein said float member has an upstanding wall about the flow aperture therein to provide a channel opening at said one opening in said housing sidewall for receiving liquid passing therethrough.

4. The skimmer of claim 1 wherein said skimmer includes a strainer member removably mounted in said housing above said discharge flow outlet therefrom, and wherein said skimmer includes means releasably engaging said float assembly in said housing, said float assembly being removable from said housing to permit access to said strainer for removal thereof.

5. The skimmer of claim 1 wherein said base member of said plate assembly has a plurality of said flow control flow openings including an opening therein adapted to receive the end of a vacuum cleaner hose fitting.

6. The skimmer of claim 5 wherein said base member comprises and elongated backing plate having a solid portion adjacent one end and said control flow openings adjacent the opposite end thereof, said cover member being provided by a throttle plate slidably mounted against one surface of said backing plate to slide from a position of registry with said solid portion to a position overlying said control flow openings and thereby closing said openings so that said throttle plate and solid portion cooperate to completely block the flow of liquid through said control flow passage, said opening in said base member adapted for receiving a hose fitting being adjacent said olpposite end of said backing plate.

7. he skimmer of claim 1 including a cap member msertable into said aperture of said float member so as to seal said flow conduit.

8. The skimmer of claim 1 wherein said plate assembly includes a frame member overlying said base member and cover member, said frame member providing a slide track for said cover member.

9. In a surface skimmer for mounting on the sidewall of a liquid-containing tank, the combination comprising:

a. a housing having a sidewall with at least one large opening in its front face providing a flow passage thereinto, said housing also having a flow outlet therefrom below said one opening and adjacent the lower end thereof for discharge of liquid;

b. a float assembly in said housing including a float member adapted to rise and fall with the level of water in said housing and to control the flow of water passing through said large opening into the lower portions of said housing;

c. a throttle plate assembly in the lower portion of the front face of said housing to permit the flow of liquid from the tank therethrough into the interior of said housing bypassing said float member, said throttle plate assembly providing adjustability of flow rate through a multiplicity of flow rates and comprising an elongated backing plate having a solid portion adjacent one end and at least one control flow opening adjacent the opposite end thereof, a throttle plate dimensioned and configured to block said control flow opening when in registry therewith, and means mounting said throttle plate against one surface of said backing plate for progressive sliding movement thereof from a position of registry over said control opening wherein said throttle plate cooperates with said solid portion to block the flow of liquid through said throttle plate assembly; and

d. support means on said housing for mounting on the sidewall of a tank.

10. The surface skimmer of claim 9 wherein said backing plate has a plurality of said control flow openings therein, and wherein one of said control openings is adapted to receive the end of a vacuum cleaner hose fitting.

k i i t 

1. In a surface skimmer supportable on the sidewall of a liquidcontaining tank and adapted for disposition substantially entirely inwardly thereof, the combination comprising: a. a unitary housing having a sidewall with at least one large opening in its front face providing a flow passage thereinto, said housing also having a flow outlet therefrom below said one opening and adjacent the lower end thereof for discharge of liquid; b. a slide plate assembly mounted on said housing in the lower portion of said large opening and extending thereacross to provide a closure for said lower portion of said opening; C. a float assembly in said housing including a float member adapted to rise and fall substantially vertically with changes in the level of water in said housing, a base member secured in said housing with its front portion supported on said plate assembly and a vertically extensible sleeve extending between said base member and said float member, said base member extending transversely of the internal cavity defined by said sidewall of said housing to provide a transverse flow barrier therein, said float and base members having apertures therein about which said sleeve extends to provide a flow conduit from the upper surface of said float member, through said sleeve, and into the lower portion of said housing for discharge of liquid through said flow outlet; said throttle plate assembly providing adjustability of flow rate through a multiplicity of flow rates and comprising an elongated backing plate having a solid portion adjacent one end and at least one control flow opening adjacent the opposite end thereof, a throttle platE dimensioned and configured to block said control flow opening when in registry therewith, and means mounting said throttle plate against one surface of said backing plate for progressive sliding movement thereof from a position of registry over said control opening wherein said throttle plate cooperates with said solid portion to block the flow of liquid through said throttle plate assembly; and d. support means on said housing for mounting on the sidewall of a tank.
 2. The skimmer of claim 1 wherein said float member includes buoyant means providing enhanced buoyancy thereto.
 3. The skimmer of claim 2 wherein said float member has an upstanding wall about the flow aperture therein to provide a channel opening at said one opening in said housing sidewall for receiving liquid passing therethrough.
 4. The skimmer of claim 1 wherein said skimmer includes a strainer member removably mounted in said housing above said discharge flow outlet therefrom, and wherein said skimmer includes means releasably engaging said float assembly in said housing, said float assembly being removable from said housing to permit access to said strainer for removal thereof.
 5. The skimmer of claim 1 wherein said base member of said plate assembly has a plurality of said flow control flow openings including an opening therein adapted to receive the end of a vacuum cleaner hose fitting.
 6. The skimmer of claim 5 wherein said base member comprises and elongated backing plate having a solid portion adjacent one end and said control flow openings adjacent the opposite end thereof, said cover member being provided by a throttle plate slidably mounted against one surface of said backing plate to slide from a position of registry with said solid portion to a position overlying said control flow openings and thereby closing said openings so that said throttle plate and solid portion cooperate to completely block the flow of liquid through said control flow passage, said opening in said base member adapted for receiving a hose fitting being adjacent said opposite end of said backing plate.
 7. The skimmer of claim 1 including a cap member insertable into said aperture of said float member so as to seal said flow conduit.
 8. The skimmer of claim 1 wherein said plate assembly includes a frame member overlying said base member and cover member, said frame member providing a slide track for said cover member.
 9. In a surface skimmer for mounting on the sidewall of a liquid-containing tank, the combination comprising: a. a housing having a sidewall with at least one large opening in its front face providing a flow passage thereinto, said housing also having a flow outlet therefrom below said one opening and adjacent the lower end thereof for discharge of liquid; b. a float assembly in said housing including a float member adapted to rise and fall with the level of water in said housing and to control the flow of water passing through said large opening into the lower portions of said housing; c. a throttle plate assembly in the lower portion of the front face of said housing to permit the flow of liquid from the tank therethrough into the interior of said housing bypassing said float member, said throttle plate assembly providing adjustability of flow rate through a multiplicity of flow rates and comprising an elongated backing plate having a solid portion adjacent one end and at least one control flow opening adjacent the opposite end thereof, a throttle plate dimensioned and configured to block said control flow opening when in registry therewith, and means mounting said throttle plate against one surface of said backing plate for progressive sliding movement thereof from a position of registry over said control opening wherein said throttle plate cooperates with said solid portion to block the flow of liquid through said throttle plate assembly; and d. support means on said housing for mounting on the sidewall of a tank.
 10. The surface skimmer of claim 9 whereIn said backing plate has a plurality of said control flow openings therein, and wherein one of said control openings is adapted to receive the end of a vacuum cleaner hose fitting. 